Antenna structure and plasma generating device

ABSTRACT

An antenna structure includes four induction antennas which have the same structure, are connected in parallel and are disposed to be overlapped. The induction antennas include an external upper section arranged on a first quadrant of a first layer, an internal upper section connected to the external upper section and arranged on a second quadrant of the first layer, an internal lower section connected to the internal upper section and arranged on a third quadrant of a second layer arranged on a lower part of the first layer, and an external lower section connected to the internal lower section and arranged on a fourth quadrant of the second layer. An RF power is supplied to one end of the external upper section, and the other end of the external lower section is grounded.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional of U.S. application Ser. No. 13/990,840, filed onMay 31, 2013, with a 371(c) date of Jul. 2, 2013, which is a NationalPhase of PCT/KR2011/006887, filed Sep. 16, 2011, the entire contents ofeach of which are hereby incorporated by reference.

TECHNICAL FIELD

The inventive concepts described herein relate to a plasma generatingdevice, and more particularly, relate to an antenna structure capable ofgenerating inductive coupling plasma

Background Art

Large-scaled substrates such as a semiconductor substrate, a flat paneldisplay substrate, a solar cell substrate, etc. may necessitatelarge-scaled fabricating devices for treating them. A plasma treatmentdevice may be used for various processes such as etching, deposition,ion implantation, material surface treatment, etc.

DISCLOSURE Technical Problem

The present invention provides an antenna structure capable of formingplasma uniformly.

The present invention also provides a plasma generating device capableof forming plasma uniformly.

Technical Solution

The antenna structure includes four induction antennas which have thesame structure, are connected in parallel and are disposed to beoverlapped. The induction antennas include an external upper sectiondisposed on a first quadrant of a first layer, an internal upper sectionconnected to the external upper section and disposed on a secondquadrant of the first layer, an internal lower section connected to theinternal upper section and disposed on a third quadrant of a secondlayer disposed on a lower part of the first layer, and an external lowersection connected to the internal lower section and disposed on a fourthquadrant of the second layer. An RF power is supplied to one end of theexternal upper section, and the other end of the external lower sectionis grounded.

Advantageous Effects

With an embodiment of the present invention, an antenna structureprovides inductive coupling plasma stably and uniformly.

DESCRIPTION OF DRAWINGS

FIG. 1A is a diagram schematically illustrating an antenna structureaccording to an embodiment of the present invention.

FIG. 1B is a plan view of an antenna structure of FIG. 1A.

FIG. 1C is a cross-sectional view taken along a line I-I′ of FIG. 1B.

FIG. 2A is a diagram schematically illustrating an antenna structureaccording to another embodiment of the present invention.

FIG. 2B is a plan view of an antenna structure of FIG. 2A.

FIG. 2C is a cross-sectional view taken along a line II-II′ of FIG. 2B.

FIG. 3A is a diagram schematically illustrating an antenna structureaccording to still another embodiment of the present invention.

FIG. 3B is a cross-sectional view of an antenna structure of FIG. 3A.

FIG. 4 is a diagram schematically illustrating an antenna structureaccording to still another embodiment of the present invention.

FIG. 5 is a diagram schematically illustrating a plasma generatingdevice according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a plasma generating device of FIG.5.

FIG. 7 is a diagram schematically illustrating a plasma generatingdevice according to another embodiment of the present invention.

MODE FOR INVENTION

A large-scaled plasma treatment device has to secure high plasmadensity, uniformity of plasma density, and process repeatability.Inductive coupling plasma may obtain high plasma. However, it isdifficult to secure uniformity of plasma.

The present invention will now be described in detail with reference tothe accompanying drawings, in which preferred embodiments of theinvention are shown. However, the inventive concept is not limitedthereto. Rather, embodiments introduced here may be provided such thatdisclosed contents become thorough and perfect and the spirit of thepresent invention is sufficiently provided to one skilled in the art. Infigures, thickness of layers (or, films) and areas may be exaggeratedlyillustrated. Also, in a case where a layer (or, film) is described to beput “on” another layer (or, film) or a substrate, a layer (or, film) maybe directly put on another layer (or, film) or a substrate or on anotherlayer (or, film) or a substrate with a third layer (or, film) interposedtherebetween. Portions marked by the same reference numbers over thespecification may indicate the same constituent elements.

FIG. 1A is a diagram schematically illustrating an antenna structureaccording to an embodiment of the present invention.

FIG. 1B is a plan view of an antenna structure of FIG. 1A.

FIG. 1C is a cross-sectional view taken along a line I-I′ of FIG. 1B.

Referring to FIGS. 1A to 1C, the antenna structure 100 may include fourinduction antennas 101 which have the same structure, are connected inparallel with one another, and are disposed to be overlapped. Each ofthe induction antennas 101 may include an external upper section 110disposed on a first quadrant of a first layer; an internal upper section112 connected to the external upper section 110 and disposed on a secondquadrant of the first layer; an internal lower section 122 connected tothe internal upper section 112 and disposed on a third quadrant of asecond layer disposed at a lower part of the first layer; and anexternal lower section 120 connected to the internal lower section 122and disposed on a fourth quadrant of the second layer. One ends P1, P2,P3, and P4 of the external upper sections 110 may be supplied with an RFpower, and the other ends G1, G2, G3, and G4 of the external lowersections 120 may be grounded. The induction antennas 101 may be rotatedby 90 degrees with respect to a central axis to be overlapped with oneanother.

In the antenna structure 100 according to an embodiment of the presentinvention, four induction antennas 101 may be electrically connected inparallel with one another. This may allow the antenna structure 100 tohave low impedance, so that a high current is applied. Also, each of theinduction antennas 101 may be interconnected without disconnection toform a loop. In this case, the induction antennas 101 may substantiallyform a closed loop to generate a maximal inducted electromotive force. Asymmetrical shape of the antenna structure 100 may enable a symmetricalproperty of plasma in a rotation direction to be improved. Also,external sections 110 and 120 may form plasma outside, and the internalsections 112 and 122 may form plasma inside. Thus, radial uniformity ofplasma may be improved.

The induction antennas 101 may be supplied with the RF power at thefirst layer and grounded at the second layer. Also, a current may flowthrough the induction antennas 101 in one direction such as a clockwisedirection or counterclockwise direction. Thus, with the bi-levelstructure, it is possible to suppress such a phenomenon that a plasmadensity is locally increased due to capacitive coupling and inductivecoupling at a location where the RF power is supplied.

The external upper section 110 may have a first curvature radius, andmay be disposed at the first quadrant of the first layer. The externalupper section 110 may have a metal or metal alloy strip or pipe shape.Desirably, the external upper section 110 may be formed of silver orgold plated copper. The external upper section 110 may have a thicknessranging from several millimeters to dozens millimeters. Desirably, theexternal upper section 110 may have a thickness ranging from 10millimeters to 20 millimeters. The external upper section 110 can have athickness of about several millimeters. One end of the external uppersection 110 may be supplied with the RF power. The external uppersections 110 may be symmetrically disposed to form a peripheral area.

The internal upper section 112 may have a second curvature radius, andmay be disposed on the second quadrant at substantially the same planeas the first layer. The internal upper section 112 may be disposed in anarea which is formed by the external upper sections 110. The firstcurvature radius may be more than the second curvature radius. A currentmay flow into the induction antenna 101 in a clockwise direction. Theinternal upper sections 112 may be adjacent to the external uppersections, and may be disposed continuously in a rotation direction.

An upper branch 114 may connect the other end of the external uppersection 110 and one end of the internal upper section 112. The upperbranch 114 may be formed of the same material as that of the externalupper section 110. The upper branch 114 and the external upper section110 may be connected by electric connection means such as bolts and/orwelding. The upper branch 114 and the internal upper section 112 may beconnected by electric connection means such as bolts and/or welding.

A vertical branch 130 may connect the other end of the internal uppersection 112 and one end of the internal lower section 122. The verticalbranch 130 may connect the first layer and the second layer.

The internal lower sections 122 may be adjacent to the internal uppersections 112, and may be disposed continuously in a rotation direction.

The internal lower section 122 may be disposed at the second layerdisposed under the first layer. The internal lower section 122 may bedisposed on the third quadrant. An interval between the first layer andthe second layer may be several millimeters to dozens millimeters.Desirably, an interval between the first layer and the second layer maybe 10 millimeters to 15 millimeters. The internal lower section 122 mayhave the second curvature radius. An insulator 103 may be disposedbetween the first layer and the second layer.

A lower branch 124 may connect the other end of the internal lowersection 122 and one end of the external lower section 120.

The external lower section 120 may be disposed on the fourth quadrant ofthe second layer. The external lower section 120 may have the firstcurvature radius. The other end of the external lower section 120 may begrounded.

Widths of the internal lower and upper sections 122 and 112 may be widerthan those of the external lower and upper sections 120 and 110. Thus, aplasma generation space formed by the external upper section 110 and theexternal lower section 120 may be reduced, and a plasma generation spaceformed by the internal upper section 112 and the internal lower section122 may be increased. This may mean that plasma uniformity in a radialdirection increases.

To form large area plasma according to a large scaled plasma generatingdevice, the RF power supplied to the antenna structure may run to nearlyseveral KW to dozens KW. Also, divice's simplicity may be required. Inrecent years, to form large area plasma according to a large scaledplasma generating device, the RF power supplied to the antenna structuremay run to nearly several KW to dozens KW. Thus, cooling may be requiredfor thermal stability of the antenna structure 100. Also, device'ssimplicity may be required. Thus, the induction antennas 101 may have apipe shape, and may be cooled by refrigerant such as air or fluid. Therefrigerant may flow through insides of the induction antennas 101.

FIG. 2A is a diagram schematically illustrating an antenna structureaccording to another embodiment of the present invention.

FIG. 2B is a plan view of an antenna structure of FIG. 2A.

FIG. 2C is a cross-sectional view taken along a line II-II′ of FIG. 2B.

Referring to FIGS. 2A to 2C, the antenna structure 200 may include fourinduction antennas 201 which have the same structure, are connected inparallel with one another, and are disposed to be overlapped. Each ofthe induction antennas 201 may include an external upper section 210disposed on a first quadrant of a first layer; an internal upper section212 connected to the external upper section 210 and disposed on a secondquadrant of the first layer; an internal lower section 222 connected tothe internal upper section 212 and disposed on a third quadrant of asecond layer disposed at a lower part of the first layer; and anexternal lower section 220 connected to the internal lower section 222and disposed on a fourth quadrant of the second layer. One ends P1, P2,P3, and P4 of the external upper sections 210 may be supplied with an RFpower, and the other ends G1, G2, G3, and G4 of the external lowersections 220 may be grounded. The induction antennas 201 may be rotatedby 90 degrees with respect to a central axis to be overlapped with oneanother.

In the antenna structure 200 according to an embodiment of the presentinvention, four induction antennas 201 may be electrically connected inparallel with one another. This may allow the antenna structure 200 tohave low impedance, so that a high current is applied. Also, each of theinduction antennas 201 may be interconnected without disconnection toform a loop. In this case, the induction antennas 201 may substantiallyform a closed loop to generate a maximal inducted electromotive force. Asymmetrical shape of the antenna structure 200 may enable a symmetricalproperty of plasma in a rotation direction to be improved. Also, theexternal sections 210 and 220 may form plasma outside, and the internalsections 212 and 222 may form plasma inside. Thus, radial uniformity ofplasma may be improved.

The induction antennas 201 may be supplied with the RF power at thefirst layer and grounded at the second layer. Also, a current may flowthrough the induction antennas 201 in one direction such as a clockwisedirection or counterclockwise direction. Thus, with the bi-levelstructure, it is possible to suppress such a phenomenon that a plasmadensity is locally increased due to capacitive coupling and inductivecoupling at a location where the RF power is supplied.

The external upper section 210 may be bent at a right angle, and may bedisposed on the first quadrant of the first layer. The external uppersection 210 may have a metal or metal alloy strip or pipe shape.Desirably, the external upper section 210 may be formed of silver orgold plated copper. The external upper section 210 may have a thicknessranging from several millimeters to dozens millimeters. Desirably, theexternal upper section 210 may have a thickness ranging from 10millimeters to 20 millimeters. The external upper section 210 can have athickness of about several millimeters. One end of the external uppersection 210 may be supplied with the RF power. The external uppersections 210 may be symmetrically disposed to form a peripheral area.

The internal upper section 212 may be bent at a right angle, and may bedisposed on the second quadrant at substantially the same plane as thefirst layer. The internal upper section 212 may be disposed in an areawhich is formed by the external upper sections 210. An area occupied bythe internal upper section 212 may be wider than an area occupied by theexternal upper section 210. A current may flow into the inductionantenna 201 in a clockwise direction. The internal upper sections 212may be adjacent to the external upper sections, and may be disposedcontinuously in a rotation direction.

An upper branch 214 may connect the other end of the external uppersection 210 and one end of the internal upper section 212. The upperbranch 214 may be formed of the same material as that of the externalupper section 210. The upper branch 214 and the external upper section210 may be connected by electric connection means such as bolts and/orwelding. The upper branch 214 and the internal upper section 212 may beconnected by electric connection means such as bolts and/or welding.

A vertical branch 230 may connect the other end of the internal uppersection 212 and one end of the internal lower section 222. The verticalbranch 230 may connect the first layer and the second layer.

The internal lower sections 222 may be adjacent to the internal uppersections 212, and may be disposed continuously in a rotation direction.The internal lower section 222 may be disposed at the second layerdisposed under the first layer. The internal lower section 222 may bedisposed on the third quadrant. An interval between the first layer andthe second layer may be several millimeters to dozens millimeters.Desirably, an interval between the first layer and the second layer maybe 10 millimeters to 15 millimeters. The internal lower section 222 maybe bent at a right angle.

A lower branch 224 may connect the other end of the internal lowersection 222 and one end of the external lower section 220.

The external lower section 220 may be disposed on the fourth quadrant ofthe second layer. The external lower section 220 may be bent at a rightangle. The other end of the external lower section 220 may be grounded.

Widths of the internal lower and upper sections 222 and 212 may be widerthan those of the external lower and upper sections 220 and 210. Thus, aplasma generation space formed by the external upper section 210 and theexternal lower section 220 may be reduced, and a plasma generation spaceformed by the internal upper section 212 and the internal lower section222 may be increased. This may mean that plasma uniformity in a radialdirection increases.

FIG. 3A is a diagram schematically illustrating an antenna structureaccording to still another embodiment of the present invention.

FIG. 3B is a cross-sectional view of an antenna structure of FIG. 3A.

Referring to FIGS. 3A and 3B, the antenna structure 100 a may includefour induction antennas 101 a which have the same structure, areconnected in parallel with one another, and are disposed to beoverlapped. the induction antennas 101 a may include an external uppersection 110 a disposed on a first quadrant of a first layer 141; aninternal upper section 112 a connected to the external upper section 110a and disposed on a second quadrant of a second layer 142 disposed at anupper part of the first layer; an internal lower section 122 a connectedto the internal upper section 112 a and disposed on a third quadrant ofa third layer 143 disposed at a lower part of the second layer; and anexternal lower section 120 a connected to the internal lower section 112a and disposed on a fourth quadrant of a fourth layer 144 disposed at alower part of the first layer 141. One end of the external upper section110 a may be supplied with an RF power, and the other end of theexternal lower section 120 a may be grounded.

An upper branch 114 a may connect the other end of the external uppersection 110 a and one end of the internal upper section 112 a. Avertical branch 130 a may connect the other end of the internal uppersection 112 a and one end of the internal lower section 122 a. A lowerbranch 124 may connect the other end of the internal lower section 122 aand one end of the external lower section 120 a.

FIG. 4 is a diagram schematically illustrating an antenna structureaccording to still another embodiment of the present invention.

Referring to FIG. 4, the antenna structure 300 may include two inductionantennas 301 which have the same structure, are connected in parallelwith one another, and are disposed to be overlapped. the inductionantennas 301 may include an external upper section 310 disposed over afirst quadrant and a second quadrant of a first layer; an internal uppersection 312 connected to the external upper section 310 and disposedover a third quadrant and a fourth quadrant of the first layer; aninternal lower section 322 connected to the internal upper section 312and disposed over a first quadrant and a second quadrant of a secondlayer disposed at a lower part of the first layer; and an external lowersection 320 connected to the internal lower section 322 and disposedover a third quadrant and a fourth quadrant of the second layer. One endof the external upper section 310 may be supplied with an RF power, andthe other end of the external lower section 320 may be grounded.

An upper branch 314 may connect the other end of the external uppersection 310 and one end of the internal upper section 312. A verticalbranch 330 may connect the other end of the internal upper section 312and one end of the internal lower section 322. A lower branch 324 mayconnect the other end of the internal lower section 322 and one end ofthe external lower section 320.

FIG. 5 is a diagram schematically illustrating a plasma generatingdevice according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a plasma generating device of FIG.5. Referring to FIGS. 5 and 6, a plasma generating device may include avacuum container 50, a dielectric unit 58 disposed at a part of thevacuum container 50, and an antenna structure for plasma generation 400a and 400 b disposed on the dielectric unit 58. The antenna structure400 a and 400 b may include a first antenna structure 400 a and a secondantenna structure 400 b. The first antenna structure 400 a may bedisposed in the second antenna structure 400 b.

The first antenna structure 400 a and the second antenna structure 400 bmay be connected to a power distribution unit 62. The power distributionunit 62 may distribute a power to the first antenna structure 400 a andthe second antenna structure 400 b. The power distribution unit 62 maybe formed of passive elements such as inductors, capacitors, and so on.

An RF power 66 may supply a power to the antenna structure 400 a and 400b through an impedance matching network 64 and the power distributionunit 62. The first antenna structure 400 a and the second antennastructure 400 b may be electrically connected in parallel. The antennastructure may include four induction antennas which have the samestructure, are connected in parallel with one another, and are disposedto be overlapped. Each of the induction antennas may include an externalupper section disposed on a first quadrant of a first layer; an internalupper section connected to the external upper section and disposed on asecond quadrant of the first layer; an internal lower section connectedto the internal upper section and disposed on a third quadrant of asecond layer disposed at a lower part of the first layer; and anexternal lower section connected to the internal lower section anddisposed on a fourth quadrant of the second layer. One end of theexternal upper section may be supplied with an RF power, and the otherend of the external lower section may be grounded.

FIG. 7 is a diagram schematically illustrating a plasma generatingdevice according to another embodiment of the present invention.

Referring to FIG. 7, the plasma generating device may include a vacuumcontainer 50, a dielectric unit 58 a disposed at a part of the vacuumcontainer 50, and an antenna structure for plasma generation 100disposed on the dielectric unit 58 a.

The dielectric unit 58 a may include a plurality of dielectric portionsspaced apart from one another. The antenna structure 100 may include aplurality of antenna structures spaced apart from one another. Theantenna structures may be put on corresponding dielectric portions,respectively.

With a modified embodiment of the present invention, the antennastructure may be changed with an antenna structure described withreference to FIGS. 1 to 4.

1. An antenna structure for plasma generation, comprising: two inductionantennas which have the same structure, are connected in parallel withone another, and are disposed to be overlapped, wherein the inductionantennas comprises: an external upper section disposed over a firstquadrant and a second quadrant of a first layer; an internal uppersection connected to the external upper section and disposed over athird quadrant and a fourth quadrant of the first layer; an internallower section connected to the internal upper section and disposed overa first quadrant and a second quadrant of a second layer disposed at alower part of the first layer; and an external lower section connectedto the internal lower section and disposed over a third quadrant and afourth quadrant of the second layer, wherein one end of the externalupper section is supplied with an RF power, and the other end of theexternal lower section is grounded.
 2. The antenna structure of claim 1,further comprising: an upper branch connecting the other end of theexternal upper section and one end of the internal upper section; avertical branch connecting the other end of the internal upper sectionand one end of the internal lower section; and a lower branch connectingthe other end of the internal lower section and one end of the externallower section.